Researchers at King’s College London and Osaka University in Japan have identified the chemical that summons stem cells from bone marrow to wound sites. The discovery could lead to new leg ulcer treatments, they said.

“The key achievement has been to find out which bone marrow cells can transform into skin cells and repair and maintain the skin as healthy tissue,” said Professor John McGrath. He heads of the Genetic Skin Disease Group at King’s. He recently spent several months working on the project in Osaka.

Scientists were already aware that bone marrow may play a role in helping skin heal. But it was not known which specific bone marrow cells this involves, how the process is triggered or how the key cells are recruited to the affected skin area.

To learn these answers, investigators conducted experiments on mice. Specifically, they looked at the mechanisms involved with skin grafts and wound healing.

The team also identified the signal that triggers recruitment of the bone marrow cells to repair skin. Damaged skin can release a distress protein called HMGB1 that can mobilize the cells from bone marrow to where they are needed.